In my limited experience the most important thing is the contact between the CPU and heatsink. Lapping the heatsink is the best thing to do before adding any TIM. After you lap it, you will find that there is hardly any real difference between expensive TIM and the cheap white stuff assuming the contact across the CPU is evenly balanced.

In my limited experience the most important thing is the contact between the CPU and heatsink. Lapping the heatsink is the best thing to do before adding any TIM. After you lap it, you will find that there is hardly any real difference between expensive TIM and the cheap white stuff assuming the contact across the CPU is evenly balanced.

True but some of us give importance at those 3/4 degrees less achieved with the better TIM

I have used Arctic Silver pastes since 2002, but I simply don't think that they are up with the times.

I'm a big fan of the "Tinting" method of application, as ideally you will have as absolutely little paste as possible between the two surfaces. The last thing you want is for the paste to become a thermal barrier, and the significant majority of applications I've seen (in person, working on people's computers) have about 3-10x more than is needed. I take issue with the "size of a pea" saying, because, well, get out a pea.... It's quite big! The proper size is more like "a .177cal BB", if you are not doing anything special (ie just pressure mounting).

After getting consistently less than ideal results with AS5, on everything from an AMD A64 FX-51 to P4EE to C2D/Q and such, I began trying different pastes. Some are super easy to apply, some provide a great temp drop, others are non-conductive, but the fact is that there aren't many that can do everything well.

Enter Prolimatech PK1. I can honestly say that it is as close to a perfect paste as you can buy. It beats the legendary (and seemingly always hard to find) Shin Etsu pastes, it outperforms MX4 and Tuniq's best offering, and it even works better and more consistently than IC Diamond 24k, one of the best pastes and one of the few that has aged well. PK1 is perfect for tinting but it's just as good for simpler applications, you can use it on anything, and I have never not seen it drop temps at least 3C (usually between 5-9C), although I realize that some of that may be a better mount/application. I did see a 13C drop under load on a Phenom II X4 960T using a 212+ Evo that I had applied (properly) some AS Ceramique too about 3mo prior.

Don't risk lapping if you're using a SB CPU or newer, I have only ever seen it ruin warranties, and maybe a 1-2C drop under load...

Saw this recently in the delidded thread. Definitely delid your chip to see the biggest temp difference. Most people around 4.5ghz are getting around your temps with just air cooling delidded. Also cores vary in temp so your are not a big deal.